Rotary drum for cooling castings



Sept. 30, 1969 H. VISSERS ROTARY DRUM FOR COOLING CASTINGS Filed Jan.16. 1968 0uooocoooooo POE &

I N VENTOR VissERs HERBERT- ATTORNEYS United States Patent U.S. C].34-13 3 Claims ABSTRACT OF THE DISCLOSURE A rotary drum adapted toreceive the hot castings and mold sand contents of mold flasks isprovided near its discharge end with a circumferentially perforatesection for separating the dried sand with its remaining sectionimperforate. A perforated lining is positioned within the and spacedfrom the drum and extends over at least part of the length of theimperforate section so as to improve tumbling contact between sand andcastings in that section by cycling sand continuousl into the spacebetween the liner and drum and then back into the liner as the drum andliner rotate.

This invention relates to an improvement of the rotary drum for coolingcastings and for cooling and drying the mold sand used for saidcastings, the contents of the flasks being dumped into the rotary drum,having an imperforate foremost section and a perforated section joinedto said first section, as described in patent application 489,714 ofSept. 23, 1965, now Patent No 3,388,478, patented June 18, 1968.

After dumping the mold sand and solidified casting contents of the moldflasks into the rotary drum the castings and the sand remain in intimatecontact with each other and as the mean temperature of the sand is muchlower than that of the castings, heat from the castings will betransmitted to the loose sand, whereby the castings are cooled and themoisture contained in the sand will evaporate, so that the heat taken upby the sand will be withdrawn and the sand will be dried.

The invention has for its object to accelerate the cooling of thecastings and the sand and according to the invention a perforated liningis provided at least along a part of the length of the foremost drumsection, where the wall of the drum is imperforated, said liningrotating together with the drum and defining a circumferential spacewith the wall of the drum. With said embodiment of the drum, sand willfall into the space defined between the lining and the wall of the drumthrough the lining perforations and upon further rotation of the drumthe sand will fall back through the perforations in the lining and willcome into contact with the castings to extract heat therefrom.

The invention will be further described with reference to theaccompanying drawing showing an embodiment of the drum according to theinvention.

FIG. 1 is a side view of the drum with part in section and FIG. 2 is anend view of the drum.

A lining 3 is provided in the drum 1 which in its rearmost part isprovided with perforations 2 and said lining has perforations 4 andextends at least along part 3,469,324 Patented Sept. 30, 1969 of thelength of the imperforated part of the drum. The perforated lining 3 issupported in the drum by means of beams 5 extending in longitudinaldirection so that a space 6 is left between the lining and the Wall ofthe drum.

The drum 1 is supported in a frame 7 on which a driving shaft 9 with amotor 8 are supported. Two chain wheels 10 are secured on the shaft 10and drive chains 11 engaging a toothed rim arranged on the drum impartrotary drive to the latter. The flasks after having been subjected to aninitial cooling are opened and dumped into a casing 13 at 12, saidcasing opening into the open foremost end of the drum, so that the sandconstitutes a slope at said end of the drum and the castings aresurrounded by humid sand, whereby the heat of the castings is withdrawnvery uniformly, so that stresses due to shrinking of the castings areavoided. The transport of the castings and the sand in the drum may beobtained by blades secured at the inner side of the perforated liningand already partly dried sand falls through the perforations 4 of thelining into the space 6 and is moved upwards in order to fall back inthe drum when the perforations reach their highest position so that thesand again comes into contact with the castings. The now completely dryand ground sand leaves the drum at the rearmost part through theperforations 2 and the castings leave the drum at its open end at 15.

The space 6 between the perforated lining 3 and the circumferential wallof the drum 1 may be divided in compartments by means of partitions.

A fan 17 draws air through the drum by means of a conduit 14 connectedto the casing 13 and which conduit opens into a dust separator 16 sothat said air carries away the water vapour, dust and broken quartzgrains from the drum.

What I claim is:

1. In a machine for cooling castings and drying mold sand of the typeincluding a substantially horizontal drum, means mounting said drum forrotation about its longitudinal axis, said drum having an inlet openingat one end and a discharge opening at its other end, and said drumhaving an imperforate section adjacent said inlet opening and aperforate section adjacent said discharge opening whereby castings andmold sands are comingled within said imperforate section, mold sand isseparated from the castings and discharged at said perforate section,and castings are discharged at said discharge opening, the improve mentcomprising:

a liner disposed within said drum along at least a part of the length ofsaid imperforate section, said liner being secured for rotation withsaid drum and defining a sand-receiving space between the liner anddrum,

means for introducing mold sand and solidified casting contents of moldflasks into said liner,

and said liner being perforate to allow sand to recycle from theinterior of the liner whereat the castings and mold sand comingle, intosaid sand-receiving space and back into the interior of said liner inresponse to rotation of said drum and liner, whereby to enhance thecooling of the castings by the sand and the drying of the sand by thecastings.

2. In the machine as defined in claim 1 including a stationary casingfor initially receiving the castings and mold sand, said casingdischarging directly into said liner.

3. In the method of cooling castings and for drying the mold sand usedfor such castings which includes the steps References Cited of dumpingthe mold sand and solidified casting contents of mold flasks into arotatable drum while the castings UNITED STATES PATENTS are still hot,tumbling the casting in intimate contact with 832,961 10/1906 Elkus34136 XR the mold sand for a time sufiicient to cool the castings by 52,131,260 9/ 1938 Temple drying the mold sand, and then separating thedry mold 214251984 8/1947 Blackman 51 164 XR sand from the castings andseparately discharging the 2,523,258 9/ 1950 Ransohofi 5 4 dry mold sandand Castings from the rotating drum, the 1 4/1960 Bintzler 51-164improvement comprising the step of:

continuously separating some of the mold sand from 10 KENNETH W.SPRAGUE, Primary Examiner the castings and later comingling it with thecastings during the step of tumbling the castings in intimate US. Cl.X.R. contact with the mold sand. 34-136

